2.2. Characteristics of UBI images
The UBI images allow you to share container images with others. Four UBI images are offered: micro, minimal, standard, and init. Pre-build language runtime images and DNF repositories are available to build your applications.
Following characteristics apply to UBI images:
- Built from a subset of RHEL content: Red Hat Universal Base images are built from a subset of normal Red Hat Enterprise Linux content.
- Redistributable: UBI images allow standardization for Red Hat customers, partners, ISVs, and others. With UBI images, you can build your container images on a foundation of official Red Hat software that can be freely shared and deployed.
- Provide a set of four base images: micro, minimal, standard, and init.
- Provide a set of pre-built language runtime container images: The runtime images based on Application Streams provide a foundation for applications that can benefit from standard, supported runtimes such as python, perl, php, dotnet, nodejs, and ruby.
Provide a set of associated DNF repositories: DNF repositories include RPM packages and updates that allow you to add application dependencies and rebuild UBI container images.
-
The
ubi-10-baseosrepository holds the redistributable subset of RHEL packages you can include in your container. -
The
ubi-10-appstreamrepository holds Application streams packages that you can add to a UBI image to help you standardize the environments you use with applications that require particular runtimes. -
Adding UBI RPMs: You can add RPM packages to UBI images from preconfigured UBI repositories. If you happen to be in a disconnected environment, you must allowlist the UBI Content Delivery Network (
https://cdn-ubi.redhat.com) to use that feature. See the Connect to https://cdn-ubi.redhat.com solution for details.
-
The
- Licensing: You are free to use and redistribute UBI images, provided you adhere to the Red Hat Universal Base Image End User Licensing Agreement.
All of the layered images are based on UBI images. To check on which UBI image is your image based, display the Containerfile in the Red Hat Container Catalog and ensure that the UBI image contains all required content.